Globally, 314 million people are visually impaired, with 87% of this affected population residing in developing countries. Glaucoma, macular degeneration, and diabetic retinopathy are all leading causes of blindness in the United States. These diseases require routine eye exams for their effective diagnosis and management. Identifying eye diseases at an early stage is crucial to preventing the condition from worsening and causing permanent vision loss. However, the high cost of retinal imaging equipment is often prohibitive for many clinics around the world and many people forgo necessary eye exams. Thus, low-cost handheld retinal imaging tools which could be used at home, in a primary care clinic, or a pharmacy, would dramatically expand access to eye examinations. We present Ocular CellScope, a mobile ophthalmoscope device that leverages smartphone technology to effectively capture retinal images and manage patient records. Our system is the second design iteration of the existing prototype, addressing a number of usability issues associated with the lack of an integrated mobile application and ergonomically friendly design. It features an advanced optical lens attachment for the iPhone built with a custom illumination system. A mobile application has been designed to capture, store, and review retinal images, as well as record patient information. Our device is capable of producing high-quality retinal images comparable to that of high-end retinal imaging equipment currently on the market and is priced at a significant fraction of the price of current competitors.